This invention relates to a printed matter which is required to have some protection so as not to be counterfeited or falsified, such as bill (paper money), bank note, security paper, passport, credit card, or other valuable printed matter. The invention also relates to a method for printing the printed matter.
Bills (paper money), bank notes, security papers, passports, credit cards, and other valuable printed items are required, because of their nature, to be designed such that they are not easily counterfeited or falsified. There are three known measures for preventing the counterfeiting of such printed matters; the first has a plurality of small and large half tone dots applied thereto at the printing time, the second has a moire pattern, and the third is provided with a latent image (hidden letters and figures) applied thereto by properly determining the drawing direction of image lines and the quantity of ink to be applied. However, since printed matters provided with the above counter-measures against counterfeiting can be counterfeited by an ordinary photometrical process, they are not very effective for preventing counterfeiting. In addition, it is now possible to make photocopies of bills, bank notes, security papers, etc. in such a manner as to resemble the real ones by using a black and white copying machine or a color copying machine.